From 3c70f2ff18650c4794556049cd4ea22a58cc719e Mon Sep 17 00:00:00 2001
From: Christophe Troestler <Christophe.Troestler@umons.ac.be>
Date: Sun, 27 Sep 2020 23:20:52 +0200
Subject: [PATCH] Do not store the Caml_ba_array_val pointer during surface
 creation

Extracted from Cairo git-tree on November 22, 2020 by
Brett Gilio <brettg@gnu.org>
---
 src/cairo_stubs.c     | 3 ++-
 tests/image_create.ml | 5 +++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/cairo_stubs.c b/src/cairo_stubs.c
index 641ee2c..200abf3 100644
--- a/src/cairo_stubs.c
+++ b/src/cairo_stubs.c
@@ -1580,6 +1580,7 @@ static cairo_status_t caml_cairo_image_bigarray_attach_proxy
                                      caml_cairo_image_bigarray_finalize);
 }
 
+#define b (Caml_ba_array_val(vb))
 #define SURFACE_CREATE_DATA(name)                                       \
   CAMLexport value caml_cairo_image_surface_create_for_##name           \
   (value vb, value vformat, value vwidth, value vheight, value vstride) \
@@ -1588,7 +1589,6 @@ static cairo_status_t caml_cairo_image_bigarray_attach_proxy
     CAMLlocal1(vsurf);                                                  \
     cairo_surface_t* surf;                                              \
     const int width =  Int_val(vwidth);                                 \
-    struct caml_ba_array *b = Caml_ba_array_val(vb);                    \
     cairo_status_t status;                                              \
                                                                         \
     if ((b->flags & CAML_BA_MANAGED_MASK) == CAML_BA_MAPPED_FILE)       \
@@ -1610,6 +1610,7 @@ static cairo_status_t caml_cairo_image_bigarray_attach_proxy
 
 SURFACE_CREATE_DATA(data8)
 SURFACE_CREATE_DATA(data32)
+#undef b
 
 #define SURFACE_GET_DATA(type, num_dims, dims ...)                      \
   CAMLexport value caml_cairo_image_surface_get_##type(value vsurf)     \
diff --git a/tests/image_create.ml b/tests/image_create.ml
index eec98d6..b13c206 100644
--- a/tests/image_create.ml
+++ b/tests/image_create.ml
@@ -10,6 +10,7 @@ let create() =
 
 let () =
   let cr = create() in
+  printf "With Cairo handle:\n%!";
   set_source_rgb cr 1. 1. 1.;
   rectangle cr 0. 0. ~w:300. ~h:300.;
   fill cr;
@@ -21,9 +22,9 @@ let () =
   show_text cr "Hello";
   Gc.compact();  Gc.compact();
 
-  eprintf "Write image\n%!";
+  eprintf "- Write image\n%!";
   PNG.write (get_target cr) "test_image.png";
-  eprintf "Finish surface\n%!";
+  eprintf "- Finish surface\n%!";
   Surface.finish (get_target cr);
   Gc.compact()
 
-- 
2.29.2

